There is no such thing as a mean girl name. There are mean girls with all types of names. I knew a mean girl named Julie growing up, but I still don't think of Julie as a "mean girl name" because there are all types of Julie's out there. Perhaps you should focus more on a name that was popular in Virginia and Louisiana at the time these girls were born

This, exactly. Some of the "mean girls" at my school don't have what you would consider "mean girl" names. I agree with @mellowyellows suggestion of researching names that were popular in Virginia and Louisiana during whenever they were born.